This invention relates to improved apparatus and methods for forming a cut ultrasonically in a workpiece.
The invention has been developed primarily to provide a way of cutting materials which cannot be easily or effectively cut utilizing conventional equipment and methods. One such material is that sold under the trademark "Kevlar" by E.I. DuPont de Nemours, which product includes fibers of a tough resinous plastic material embedded within a resin, and which product is asserted to have a strength to weight ratio greater than any other known material. Attempts have been made to cut this material with conventional saw blades and other standard cutting tools, but with only very limited success by reason of the tendency of these blades and tools to produce a very rough gouging type of action, tearing the material apart and leaving frayed and irregular edges at both sides of the cut.
Ultrasonic equipment has been proposed in the past for machining or cutting metals and materials, but in the forms previously devised this equipment has not to my knowledge been successful in cutting KEVLAR. Such ultrasonic apparatus includes a vibration amplifying horn or other element which is vibrated along a predetermined axis by electronically energized circuitry, and which carries a cutter vibrating with the horn for producing a cut in the workpiece.